Dosatron Water Powered Doser offered by Sunlight Supply, Inc Video

http://www.sunlightsupply.com/shop/bycategory/pumps-and-irrigation-supplies/dosatron-water-powered-doser
Inject nutrients, supplements/additives and pH adjusters into irrigation water with ease. No electricity needed. Dosatron is a passive precision fertilizer doser that accurately mixes from the pressure of your incoming water. Operating pressure range is 4.3 -85 PSI and water flow range is 0.05 - 11 GPM. Injection capabilities of 1:1000 to 1:112 (0.1 - 0.9%) [3.5 ml to 35 ml per gallon]. The unit has 3/4 in NPT connections and comes 6 ft suction hose complete with strainer. 709002, 709004 and 709006 are special order only.

Sunlight Supply offers 4 models to choose from!